The present invention relates to an extendible bunk stake for use on a log truck and the like, and more particularly, to a stake which can be extended readily by manipulating an extension member in the stake with a log being loaded on the truck by a log loader.
The usual log truck has a log load area defined by longitudinally spaced bunks and upright bunk stakes mounted on outer sides of the bunks. According to conventional practice, logs are loaded into the load area by an operator-controlled boom loader. An experienced operator is able to manipulate logs being handled by the loader to load logs quickly and at accurately placed positions in the load area.
Frequently, where the truck is loaded with relatively small diameter logs, or with logs having a relatively low volume weight, a log truck will be able to carry a greater log-weight load than can be placed in the load area defined by conventional-height stakes. In situations such as these, it is common to increase the height of the load area by extending the bunk stakes.
One type of extendible stake proposed in the prior art is designed to be manually raised by an operator standing on the bunks. An operator, when on a bunk, is particularly vulnerable to being injured by logs being loaded onto the truck, and a number of serious accidents have occurred, particularly in wet weather. Another problem associated with some prior art extendible stakes is that where a stake's extension member is intended to be loosely mounted on the fixed, lower portion of the stake, the extension member may become dislodged during log loading or unloading, with consequent inconvenience or safety hazard to loading personnel.
Another type of extendible bunk stake known in the prior art is a telescopic extension member whose upper end is equipped with a fixed-position claw. The claw is adapted for engagement with a log being handled by a boom-type log loader, allowing the loader-operator to raise the extension member at a safe distance from the truck. For reasons of highway truck regulations, the claw cannot be constructed to extend substantially beyond the outwardly facing side of the extension member. Nor can the claw extend much beyond the inwardly facing side of the extension member without interferring with logs being loaded on the truck and supported by the extension members. Accordingly, one problem which has been experienced because of the fact that the claw is substantially flush with the sides of the extension member is that the loader operator may have considerable difficulty engaging the claw adequately for raising the extension member. An operator must then climb up on the bunk and manually raise the extension member.
It is a general object of the present invention to provide an extendible bunk stake which substantially overcomes the above-mentioned problems associated with prior art extendible bunk stakes.
A more specific object of the present invention is to provide such a stake having an extension member which is equipped with a releasably positionable log-engagement arm which can be moved, by manipulation of a log being handled in a log loader, toward and away from a position facilitating log engagement when the extension member is to be raised.
It is another object of the invention to provide such a stake which provides a visual indication to a log loader operator when the extension member is locked in its raised position.
Still another object of the invention is to provide such a stake having an extension member which can be raised or lowered manually by an operator at a ground position.
The extendible bunk stake of the present invention is intended for use on a log truck and the like. The stake includes an upright post adapted to be mounted on a log bunk and an extension member telescopically extendible from the post's upper end from a lowered position to a raised position, to extend the height of the stake. The extension member is releasably locked in its raised position by a spring-operated latch. An arm mounted on the member, adjacent its upper end, is pivotable between an upright and an inclined inwardly projecting position where the arm is adapted to be engaged by a log being raised adjacent the inwardly facing side of the stake, to raise the stake from its lowered toward its raised position. An arm locking device holds the arm at its inwardly projecting position by tension in a spring in the locking device, as the extension member is being raised by a log engaging the arm and being moved upwardly. When the extension member reaches the upper limit of its travel at its raised position, continued upward movement of the log overcomes the tension in the spring, to effect release of the arm for movement toward its upwardly extending position.
In a preferred embodiment of the invention, the spring-operated latch provides visual indication of when the latch is in a locking position. The stake may also include a rod attached to the extension member, for use in shifting the extension member manually from a ground position. The extension member is preferably guided on the post for axial, nonrotative shifting with respect thereto by guiding structure which permits twist-and-raise movement release of the member from the post.
These and other objects and features of the present invention will become more fully apparent when the following detailed description of preferred embodiments of the invention is read in conjunction with the accompanying drawings.